As a means for decreasing noise in playing back, there have so far been made a number of proposals to smooth magnetic recording component layers by use of ultrafine magnetic powders (see Japanese Pat. O.P.I. Pub. No. 206020/1990, etc.). In general, however, using a fine magnetic powder is liable to cause aggregation and thereby lowers the dispersibility of the magnetic powder, bringing about deterioration in electromagnetic conversion property.
Further, with the object of providing a magnetic recording medium with improved electromagnetic conversion property, there have been proposed double-layer magnetic recording media which comprise a non-magnetic support having thereon an upper layer containing a magnetic powder and a lower layer containing a non-magnetic powder (see Japanese Pat. O.P.I. Pub. Nos. 187418/1988, 191315/1988, 19524/1989, etc.). However, when applied to digital recording media which require excellent magnetic recording properties in high frequency region, these proposals cannot provide magnetic recording media having adequate properties. The reason for such unfavorable results is that the magnetic recording media proposed above are not intended for use as digital recording media. Accordingly, the magnetic recording media proposed above, though formed in double-layer structure, have a relatively thick upper layer and, as a result, their output loss due to layer thickness and self-demagnetization loss become larger, making it difficult to achieve the electromagnetic conversion property and running durability required of digital recording media.
Therefore, making the magnetic layer thinner and smoother is conceived to be a solution for the above problem. However, when a thin magnetic layer is formed on a non-magnetic layer, this upper magnetic layer tends to have a roughened surface attributable to its thinness and fails to provide an adequate playback output in high frequency region. Further, when only a hexagonal barium ferrite magnetic powder is used as a magnetic powder for the improvement of properties in high frequency region, properties in low frequency region and overwriting properties are lowered.